Life expectancy gains are slowing, study finds

Healthier diets, medical advances and other quality-of-life improvements resulted in a near-doubling of life expectancy over the course of the 20th century — but the rate of increase has slowed considerably in the last three decades.

That’s according to a new study led by the University of Illinois Chicago and published in the journal Nature Aging, which found that life expectancy at birth in the world’s longest-living populations has increased by an average of only six and a half years since 1990. That rate of improvement falls far short of some scientists’ expectations that life expectancy would increase at an accelerated pace in this century and that most people born today will live past 100 years.

According to the study’s lead author, Professor S Jay Olshansky, the biggest boosts to longevity have already occurred through successful efforts to combat disease. That leaves the damaging effects of aging as the main obstacle to further extension.

“Most people alive today at older ages are living on time that was manufactured by medicine,” Olshansky said. “But these medical Band-Aids are producing fewer years of life even though they’re occurring at an accelerated pace, implying that the period of rapid increases in life expectancy is now documented to be over.”

That also means extending life expectancy even more by reducing disease could be harmful, if those additional years aren’t healthy years. According to Olshansky, “We should now shift our focus to efforts that slow aging and extend healthspan”, referring to a relatively new metric that measures the number of years a person is healthy, not just alive.

In 1990, Olshansky published a paper in Science that argued humans were approaching a ceiling for life expectancy of around 85 years of age and that the most significant gains had already been made. The new study supports the idea that life expectancy gains will continue to slow as more people become exposed to the detrimental and immutable effects of aging. The study looked at data from the eight longest-living countries and Hong Kong, as well as the United States — one of only a handful of countries that has seen a decrease in life expectancy in the period studied.

“Our result overturns the conventional wisdom that the natural longevity endowment for our species is somewhere on the horizon ahead of us — a life expectancy beyond where we are today,” Olshansky said. “Instead, it’s behind us — somewhere in the 30- to 60-year range. We’ve now proven that modern medicine is yielding incrementally smaller improvements in longevity even though medical advances are occurring at breakneck speed.”

While more people may reach 100 years and beyond in this century, those cases will remain outliers that won’t move average life expectancy significantly higher, Olshansky said. That said, there may be more immediate potential in improving quality of life at older ages instead of extending life. The authors therefore argue that more investment should be made in geroscience — the biology of aging, which may hold the seeds of the next wave of health and life extension.

“This is a glass ceiling, not a brick wall,” Olshansky said. “There’s plenty of room for improvement: for reducing risk factors, working to eliminate disparities and encouraging people to adopt healthier lifestyles — all of which can enable people to live longer and healthier.”

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